Serum inhibin B as a marker of spermatogenesis

ABSTRACT

Serum inhibin B has emerged as a good marker of spermatogenesis and Sertoli cell function. The aim of this study was to better define the relationship between serum inhibin B level with serum follicle stimulating hormone [FSH] and the spermatogenetic function of the testis in fertile and infertile men and to evaluate the diagnostic value of inhibin B in the management of male infertility. Fifty-five infertile men [age ranged from 22-40 years with a mean of 30.4 +/- 3.2 years] were included in this study. They were divided into 3 groups; the first group was composed of 20 oligozoospermic patients [sperm concentration<20 millionl ml], the second group included 18 azoospermic patients with functional etiology, and the third group included 17 azoospermic patients with obstructive causes. Also a control group of 20 fertile subjects of comparable age was included. Andrology Outpatient Clinic, Menoufyia University Hospitals. Inhibin B and FSH were assessed in serum, semen analysis and testicular volume estimation were performed for studied and control subjects. Also testicular biopsy was done for azoospermic cases only. Mean serum inhibin B level in fertile subjects was 201.2 +/- 37.5 pg/ml, which was almost similar to the mean level in patients with azoospermia due to obstructive causes [199.2 +/- 30.5pg/ ml], while the mean level was significantly reduced in oligozoospermic patients [104.5 +/- 15.4 pg/mI] and in patients with functional azoospermia [45.3 +/- 26.2 pg/ml][P<0.0001]. Also, it was noticed that there was a positive correlation between serum inhibin B and sperm concentration, testicular volume and Johnsen's scores of testicular biopsy, while there was a negative correlation with FSH levels. It is concluded that serum inhibin B is an index of global testicular function whose secretion reflects a fundamental interaction between Sertoli cells, germ cells and FSH. Thus its measurement can offer improved diagnosis of testicular dysfunction